cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Previous Showing 11-15 of 15 results.

A006550 n+8*C(n,2)+30*C(n,3)+62*C(n,4)+75*C(n,5)+30*C(n,6).

Original entry on oeis.org

0, 1, 10, 57, 234, 770, 2136, 5180, 11292, 22599, 42190, 74371, 124950, 201552, 313964, 474510, 698456, 1004445, 1414962, 1956829, 2661730, 3566766, 4715040, 6156272, 7947444, 10153475, 12847926, 16113735, 20043982, 24742684, 30325620
Offset: 1

Views

Author

Keywords

References

  • Simon Plouffe, Approximations de séries génératrices et quelques conjectures, Dissertation, Université du Québec à Montréal, 1992.
  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 254, gives this as number of ways to color faces of a cube using at most n colors, but the formula is incorrect - see A047780.

Programs

  • Maple
    A006550:=(-1-3*z-8*z**2-10*z**3-14*z**4+6*z**5)/(z-1)**7; # conjectured by Simon Plouffe in his 1992 dissertation
  • Mathematica
    Table[n+8Binomial[n,2]+30Binomial[n,3]+62Binomial[n,4]+75Binomial[n,5]+ 30Binomial[n,6],{n,0,40}] (* or *) LinearRecurrence[{7,-21,35,-35, 21,-7,1}, {0,1,10,57,234,770,2136},40] (* Harvey P. Dale, Apr 24 2011 *)

Extensions

Jud McCranie found this error and gave the correct version of this sequence (A047780).

A006529 a(n) = (25*n^4-120*n^3+209*n^2-108*n)/6.

Original entry on oeis.org

0, 1, 10, 57, 272, 885, 2226, 4725, 8912, 15417, 24970, 38401, 56640, 80717, 111762, 151005, 199776, 259505, 331722, 418057, 520240, 640101, 779570, 940677, 1125552, 1336425, 1575626, 1845585, 2148832, 2487997, 2865810, 3285101, 3748800, 4259937, 4821642
Offset: 0

Views

Author

Keywords

References

  • M. Gardner, New Mathematical Diversions from Scientific American. Simon and Schuster, NY, 1966, p. 246, gives this as the number of ways to color faces of a cube using at most n colors, but the formula is incorrect (it was corrected in the second printing) - see A047780.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Programs

  • Maple
    A006529:=-z*(1+5*z+17*z**2+77*z**3)/(z-1)**5; [Conjectured by Simon Plouffe in his 1992 dissertation.]
  • Mathematica
    Table[(25n^4-120n^3+209n^2-108n)/6,{n,0,40}] (* or *) LinearRecurrence[ {5,-10,10,-5,1},{0,1,10,57,272},40] (* Harvey P. Dale, Oct 30 2011 *)

Formula

From Harvey P. Dale, Oct 30 2011: (Start)
a(n) = 5*a(n-1)- 10*a(n-2)+ 10*a(n-3)-5*a(n-4)+a(n-5).
G.f.: (-77*x^4-17*x^3-5*x^2-x)/(x-1)^5. (End)

Extensions

Jud McCranie noticed this error and gave the correct version of this sequence (A047780).

A282816 Number of inequivalent ways to color the faces of a cube using at most n colors so that no two opposite sides have the same color.

Original entry on oeis.org

0, 0, 1, 11, 76, 340, 1135, 3101, 7336, 15576, 30405, 55495, 95876, 158236, 251251, 385945, 576080, 838576, 1193961, 1666851, 2286460, 3087140, 4108951, 5398261, 7008376, 9000200, 11442925, 14414751, 18003636, 22308076, 27437915, 33515185, 40674976, 49066336
Offset: 0

Views

Author

David Nacin, Feb 21 2017

Keywords

Comments

Also the number of inequivalent ways to color the corners of an octahedron using at most n colors so that no two opposite corners have the same color.

Examples

			For n = 2 we get a(2) = 1 way to color the faces of a cube with two colors so that no two opposite sides have the same color.
		

Crossrefs

Cf. A282817, A047780 (face colorings without restriction).

Programs

  • Mathematica
    Table[(8n(n-1) + n^3(n-1)^3) /24, {n, 0, 35}]
  • PARI
    a(n) = n*(n-1)*(n^4-2*n^3+n^2+8)/24 \\ Charles R Greathouse IV, Feb 22 2017

Formula

a(n) = n*(n-1)*(n^4-2*n^3+n^2+8)/24.
G.f.: -x^2*(1+4*x+20*x^2+4*x^3+x^4)/(x-1)^7 . - R. J. Mathar, Feb 23 2017

A282817 Number of inequivalent ways to color the faces of a cube using at most n colors so that no color appears more than twice.

Original entry on oeis.org

0, 0, 0, 6, 72, 375, 1320, 3675, 8736, 18522, 36000, 65340, 112200, 184041, 290472, 443625, 658560, 953700, 1351296, 1877922, 2565000, 3449355, 4573800, 5987751, 7747872, 9918750, 12573600, 15795000, 19675656, 24319197, 29841000, 36369045, 44044800, 53024136
Offset: 0

Views

Author

David Nacin, Feb 21 2017

Keywords

Comments

Also the number of inequivalent ways to color the corners of an octahedron using at most n colors so that no color appears more than twice.

Examples

			For n=3 we get a(3)=6 ways to color the faces of a cube with three colors so that no color appears more than twice.
		

Crossrefs

Cf. A249460, A282816. A047780 (face colorings without restriction).

Programs

  • Mathematica
    Table[(3 n (n - 1) (n - 2)^2 + 6 n (n - 1) (n - 2) + n (n - 1) (n - 2) (n - 3) (n - 4) (n - 5) + 15 n (n - 1) (n - 2) (n - 3) (n - 4) + 45 n (n - 1) (n - 2) (n - 3) + 15 n (n - 1) (n - 2))/24, {n, 0, 16}]

Formula

a(n) = (n-2)^2*(n-1)*n^2*(n+5)/24.
G.f.: 3*x^3*(-2-10*x+x^2+x^3)/(x-1)^7 . - R. J. Mathar, Feb 23 2017

A316093 Non-isomorphic colorings of the cube under rotations, using at most N colors on the faces and M colors on the vertices. Square array H(N,M) with N,M > 0 read by antidiagonals.

Original entry on oeis.org

1, 10, 23, 57, 776, 333, 240, 8121, 17946, 2916, 800, 44608, 200961, 176160, 16725, 2226, 168675, 1124208, 1995852, 1045050, 70911, 5390, 501528, 4281300, 11198720, 11877825, 4485960, 241913, 11712, 1261701, 12773538, 42697300, 66700400, 51044337, 15385706, 701968, 23355, 2807296, 32195646, 127461216, 254387500, 286724160, 175153881, 44761216, 1798281, 43450, 5685903, 71718336, 321364540, 759518850, 1093653675, 983988208, 509689776, 114826410, 4173775
Offset: 1

Views

Author

Marko Riedel, Jun 24 2018

Keywords

Examples

			Square array begins:
     1,     10,      57,      240,      800, ...
    23,    776,    8121,    44608,   168675, ...
   333,  17946,  200961,  1124208,  4281300, ...
  2916, 176160, 1995852, 11198720, 42697300, ...
		

Crossrefs

H(N,1) (first row) is A047780. H(1,M) (first column) is A000543.

Formula

H(N,M) = (1/24) (N^6 M^8 + 6 N^3 M^2 + 3 N^4 M^4 + 8 N^2 M^4 + 6 N^3 M^4).
Cycle index is (1/24)*(a1^6 b1^8 + 6 a1^2 a4 b4^2 + 3 a1^2 a2^2 b2^4 + 8 a3^2 b1^2 b3^2 + 6 a2^3 b2^4).
Previous Showing 11-15 of 15 results.